Add a cable management hook to your server rack or cabinet for strain relief and organization the cmhook1un vertical cable management d ring lets you add a 1u metal cable hook to your server rack or cabinet to provide an organized channel for your cables constructed of high quality steel the cable d ring measures 18 x 39in 45 x 10cm and offers a flexible opening for easy insertion of bundled cables providing strain relief for attached cables multiple cable rings can be attached to y